The present invention relates to a method for removing hydrogen sulfide from waste water and in particular to a method employing redox resin material which can be used repeatedly as a result of continuous oxidation treatment.
Industrial waste water containing hydrogen sulfide presents a significant pollution problem because of its high toxicity and unpleasant odor even at low concentrations. The treatment of such waste water is necessary before discharging it to the environment so as to reduce the hydrogen sulfide content to acceptable levels. The present invention is aimed at developing a simple and effective method of performing the removal of hydrogen sulfide from such waste water streams.
In U.S. Pat. No. 4,076,621 issued Feb. 28, 1978 to I. C. Hardison, there is apparently disclosed a method of stripping hydrogen sulfide containing waste water with air and scrubbing the evolved gas with solutions containing iron chelate. The process which is described in this patent is a two stage process requiring a large equipment assembly for aeration of the waste water and a subsequent scrubbing operation. Spent chemicals employed in this process are neither recovered nor regenerated. Accordingly, this method requires high material costs because chemicals employed are spent and not recovered.
In the text "Physicochemical Processes for Water Quality Control" by N. J. Weber (Wiley-Interscience 1972) the direct production of sulfur from hydrogen sulfide in an aqueous phase is apparently disclosed using oxidizing agents such as potassium permanganate, KMnO.sub.4. However, these oxidizing agents cannot be recovered, and accordingly, this method also requires high material costs and involves a potential pollution problem generated by the excess chemicals employed.
Accordingly, it is seen that it is desirable to provide a method for removing hydrogen sulfide from waste water or other aqueous streams by means of processes which do not require the use of expendable chemical quantities nor the use of chemicals which, when employed in excess of stoichiometric requirements, can produce a pollution problem of their own. It is also seen that a method for hydrogen sulfide removal is desirable in which materials employed can be recycled, reconditioned or restored to reduce the cost of the method which would otherwise be attributable to spent chemical materials.